Ranges, Performance, and opApply

[Виталий Фадеев]

https://forum.dlang.org/post/j8nnr2$bgf$1@digitalmars.com

On Tuesday, 1 November 2011 at 03:08:18 UTC, Kapps wrote:
> Thanks for the explanation guys.

I interest this too.
Theme up.

         int opApply( scope int delegate( FT_Outline outline ) dg )
         {
             // ...more code...
             return 0;
         }


         void main()
         {
             // ...initialization code...

             foreach ( outl; outline )
             {
                 writeln( outl );
             }
         }


I tested this code in Compiler Explorer: 
https://godbolt.org/z/vnqoYsazn

With default options LDC do call the `example.FT_Outline.opApply`.

But with `-O` and when function `opApply()` marked as `pragma( 
inline, true )` then LDC put opApply() body inline. I see call 
`writeln()` directly from `_Dmain`, without call/ret | jmp.

LDC can put foreach body inline. But need to test with real-world 
application.